Perfect numbers

Write a function that tells if a natural @n@ is perfect.

A natural number is called perfect if it is equal to the sum of all its divisors except itself. For instance, 28 is perfect, because $28=1+2+4+7+14$ .

Interface

C++	`bool is_perfect(int n);`
C	`int is_perfect(int n);`
Java	`public static boolean isPerfect(int n);`
Python	`is_perfect(n) # returns bool`
	`is_perfect(n: int) -> bool`

Precondition

@n@ is a natural number.

Observation

You only need to submit the required procedure; your main program will be ignored.

Problem information

Author: Unknown
Translator: Carlos Molina

Generation: 2026-01-25T10:20:25.770Z